–Specifies access method used by Ethernet–Requires all devices to listen to cable before transmitting (carrier sense).

–When line is clear, any device can transmit (multiple access)

–If two devices transmit at same time:

collision occurs

Back off for random time period

both must retransmit (collision detection)

Describe some Ethernet advantages and disadvantages.

–Advantages:

Hardware relatively inexpensive, available.

High speed versions:

–802.3x: 100Mbps Ethernet

–802.3z: 1Gbps Ethernet

–Disadvantages:

Performance can suffer as network size increases, increasing number of possible collisions

Collisions eliminated with switching

Name a connection oriented protocol and a connectionless protocol.

Connection Oriented - TCP(Transmission Control Protocol)

Connectionless - UDP(User Datagram Protocol)

How many bits is IPv4?

32 bits(4 sets of 8)

Access protocols

Communications procedures used at the Data Link layer on all networks.

Backoff

A random amount of time each system on a network must wait before attempting to transmit when a collision has been sensed.

CSMA/CD

Used interchangeably with Ethernet. Serves as the basis for how cable is accessed for communication. All devices must listen before it can transmit (carrier sense). Only one device on the network can transmit at a time. After the line is clear, any device can send its message (multiple access). If two computers transmit at the same time, a collision occurs and both must retransmit (collision detection).

DHCP

Dynamic Host Conﬁguration Protocol. Protocol and service used to automatically provide IP address and other TCP/IP conﬁguration settings from a central host.

IP

Internet Protocol. The protocol used to assign unique addresses to devices on the Internet.

Manchester encoding

A special type of unipolar signaling in which the signal is changed from high to low or from low to high in the middle of the signal.

MAU

Media Access Unit. A unit in a Token Ring topology which passes packets to computers on the network.

Multiplexing

A communication method that allows multiple signals to transmit simultaneously across a single physical channel by varying length of transmission, frequency used, or both.

Protocol stack

The group of protocols surrounding a data packet that is added and removed as the data stack moves through the layers of the OSI model.

Protocol suite

Several network protocols grouped together, like TCP/IP.

RZ

Return to zero. This telecommunications code always returns to 0 volts after each bit before going to +5 volts (for a 1) or 5 volts (for a 0) for the next volt.

NRZ

Nonreturn to zero. This telecommunications binary code schema represents 1s and 0s with separate significant voltage conditions (for example, 1 as positive voltage and 0 as no voltage). No other conditions are recognized in this code.

Subnet mask

A portion of the IP address that identifies which part of the 32 bits is the host address and which part is the network address for the system.

TCP

Transmission Control Protocol The most common of all network protocol suites, the standard in today’s networks, and the protocol suite used for communication on the Internet. Provides connection-oriented packet delivery services that include error checking and sequence numbering, with the destination device responding with a receipt on packet delivery.

Wireless Personal Area Networks Describes short distance wireless networks used by individuals at home or office and includes PDAs, printers, smart phones, tablets and PCs. The 802.15 Wireless Personal Area Network standard is under development.

Class A

first bit is a 0

Value of the first octet is between 1 and 127 (127 loopback)

the first octet assigned, leaving the last three octets to be assigned to hosts

Intended for large corporations and government

Class B

first 2 address bit are with 10

–Value of the first octet is between 128 and 191

–The first two octets assigned, leaving the third and fourth octets to be assigned to hosts

–Intended for use in medium to large networks

Class C

first 3 address bits are 110

–Value of the first octet is between 192 and 223

–The first three octets

–These networks are limited to 254 hosts per network

–Intended for small networks

Class D

first 4 address bits are 1110

Value of the first octet is between 224 and 239

–Reserved for multicasting

Class E

first 5 address bits are 11110

–Value of the first octet is between 240 and 255

–Reserved for experimental use and can’t be used for address assignment

Reserved addresses are

Class A addresses beginning with 10

Class B addresses from 172.16 to 172.31

Class C addresses from 192.168.0 to 192.168.255

The addresses in those ranges can’t be routed across the Internet

What some properties of IPv6?

128 bit address size (16 bytes)

No class address like IPv4

Supports CIDR notation

Has many of the features of IPv4

Uses a different format for IP addresses

Can run alongside IPv4 without needing to change the Transport Layer or Network Access Layer

Describe the format of a n IPv6 address.

8 sets of 4 hexadecimal numbers

A hexadecimal number needs 4 bits.

8*4*4 = 128

The Process layer of the Internet model is the same as the ______ of the OSI model

Application, Presentation, Session layers

The Host-to-Host layer of the Internet model is the same as the ______ of the OSI model

Transport layer

The Internet layer of the Internet model is the same as the ______ of the OSI model

Network

The Network Interface layer of the Internet model is the same as the ______ of the OSI model

Data Link

The Transport layer of the OSI model is the same as the ______ of the Internet model.

Host-to-Host

The Network layer of the OSI model is the same as the ______ of the Internet model.

Internet

The Data Link layer of the OSI model is the same as the ______ of the Internet model.

The process of adding a header and a trailer to information as the data passes from computer to computer over a network

What is a header?

A set of information added to the beginning of a data packet

What is a trailer?

–A set of information added to the end of a data packet

What is a MAC?

The MAC address is permanently hard-coded on the NIC by the manufacturer.

It is a unique hexadecimal address with six pairs of hexadecimal digits and is not duplicated anywhere in the world. The first six digits are assigned to the NIC manufacturer. The last six are a unique value assigned by the manufacturer

–Conventional MAC address 48 bits (IPv6 – 64 bit MACS)

What is a NIC?

Network Adapter or Network Interface Card

What is Dialog control? Describe them?

The service responsible for determining which computer is sending and which is receiving at any given time throughout the session.

Simplex -Data flows in only one direction.

Half duplex -Data flows in both directions,but only in one direction at a time.

Full duplex-Data flows in both directions at the same time.

What is TTL?

Time to Live (TTL) An IP header field whose value is used to limit the lifespan of a datagram based on the number of routers(hops) it crosses.

What is Ack?

Acknowledgement message sent by the receiving computer in a connection oriented transmission.

Flow control

The process that limits the number of transmission ssent at one time to avoid overloading the receiving device.

Authentication mechanisms

Authentication mechanisms are ways that the network can validate who is and who isn’t allowed access to the network.

Extranet

A private network that allows for specific external users to access it over the Internet.

What is an intranet?

An intranet is a LAN that uses the same technologies as the Internet, such as using web servers to facilitate internal communications, but it’s open to only those inside the organization.

Describe the Application layer.

Layer 7 (highest layer)

Allows the end user access to the network by providing a set of utilities for application programs.

Five categories of service:

Files service

E-mail services

Network printing services

Application services

Database services

Describe the Presentation layer.

Layer 6

Data presentation - Formatting data so that it is readable by the recipient.

Data compression - Resizing the data to speed transmission.

Data encryption - Making data unreadable by unintended recipients.

What is the Session layer?

Layer 5

Responsible for initiation, maintenance, and termination of each logical session between computers. Session layer is also responsible for session accounting.

Dialog control: –Simplex, half-duplex, full duplex.

Data separation:–Inserting markers in packets to recover from loss of packets or other problems.

Describe the Transport layer.

Layer 4

deals with end-to-end issues such as procedures for entering and exiting from the network

establishes & terminate logical connections for data transfer

breaks larger samples into manageable pieces and flow control

Two types of transmission:

Connection-oriented transmission (TCP)

-It is reliable

-It allows for relatively slow communication

-Packets are re-sent if a packet is unrecognizable or is not received

Connectionless (UDP)

-Does not acknowledge receipt of the packet

-Provides a relatively faster connection

-Packets are not re-transmitted

Describe the Network layer.

Layer 3

Responsible for addressing and delivery of packets (datagrams)

IPv4 and IPv6

Performs routing:

–Finding a path through routers so packets are delivered to the correct network and then the correct computer

Each computer has:

–A physical address - coded on network card

–A logical address - assigned through networking software, used by the Network layer

Describe the Data Link layer.

Layer 2

Manages the physical transmission circuit in the Physical layer

MAC Addresses (Hardware Address or Physical Address)

Transforms it into a circuit that is free of transmission errors by performing error detection, correction, and retransmission.

Converts data packets into frames. A frame is the data packet plus the encapsulating information, including layer 2 addresses.